Weekley, C.W. , Menges, E.S. , Rickey, M.A. .
Effects of mowing and burning on Florida scrub, a fire-dependent ecosystem.
Florida scrub and its two-dozen federally listed plants depend on fire for their continued existence. However, remaining scrub habitat is often embedded in urban or suburban areas where land managers are hesitant to use prescribed fire due to risk of escape or smoke management concerns. Mechanical treatments such as mowing are being used as alternatives to, or in combination with, burning. To compare the effects of mowing as a fire surrogate or pre-treatment on the recovery of oak-rosemary scrub, we applied four contrasting treatments: mow-only, burn-only, mow+burn, and an untreated control. We measured shrub height, litter depth, percent bare sand, and the abundance of rare species before treatments and one and two years after treatments and analyzed data using repeated measures ANOVA. All treatments had similar effects in significantly reducing shrub height relative to the control. Litter depth decreased with burn and mow+burn treatments, but not in the mow-only treatment. However, the effect was temporary; two years post-treatment the litter depth was only about one-third lower than pre-treatment for both burn-only and mow+burn treatments. Bare sand, a key microsite for many scrub herbs, increased in burn treatments but mowing alone did not differ from the control. Densities of the rare plant Paronychia chartacea were highly variable, but showed the greatest increase in the burn-only treatment. The increased density was due to seedling recruitment from the soil seed bank. Mowing appears to be a poor substitute for fire. However, when used as a pre-treatment for fire, mowing produces effects similar to fire alone and may be a safe and effective way to introduce fire to long-unburned areas.
Archbold Biological Station
1 - Archbold Biological Station, Plant Ecology Lab, P.O. Box 2057, Lake Placid, Florida, 33862-2057, USA
Presentation Type: Paper
Location: Wasatch (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 8:45 AM